Sir Bradley Wiggins can win the Giro d'Italia and the Tour de France in 2013, according to Stephen Roche.

The Irishman is one of seven riders to have claimed the double Grand Tour success, achieving the feat in 1987, when he also won the World Championships road race.

Wiggins, the Tour's first British winner last July, has stated his 2013 priority is May's Tour of Italy.

But France could become a target depending on his recovery, leading to the possibility of a Team Sky leadership battle with Chris Froome.

Froome was runner-up in the 2012 Tour and finished third in the Olympics time-trial as Wiggins won gold, but is considered the more accomplished climber and more suited to the mountainous route for this summer's 100th Tour de France.

"Wiggins and (Team Sky principal Sir Dave) Brailsford know the Tour this year's going to be difficult for Bradley, because of the minimal amount of time-trialling," HotChillee ambassador Roche said.

"That doesn't mean they believe Bradley can't win it. By telling everybody Bradley is doing the Giro and the Tour is secondary to him, it's taking a lot of pressure off.

"The Giro's by no means a piece of cake - just because he won the Tour last year doesn't mean he'll win the Giro this year.

"He's capable of winning, but it must not be underestimated.

"If he wins the Giro or doesn't win the Giro, he'll still go out to win the Tour.

"If he has it in his legs he'll want to win it and logically, because he's the out-going winner, he will be the team leader."

Wiggins' Tour win featured more than 100km of time-trials, a discipline in which he is the world's leading exponent.

Although Roche believes Kenya-born Froome is better suited to the summit finishes scheduled for the 2013 edition of the race, the Irishman has backed Wiggins and his preparation, too.

"There's nearly five weeks between the Giro and the Tour," Roche added.

"For me, it's a win-win situation. If he wins it, he'll be one up on everyone else mentally. If you don't win it, you have the miles under your belt and the stamina, which will help you in the difficult days in the Tour.

"Winning the Giro and the Tour is possible and Bradley is one of the riders that can do it.

"For the moment seven riders have done it and it's a small family. If somebody else does it, it's going to make the family even bigger.

"For me, if riders still believe they can't do it, it's even better."

Team Sky have made an impressive start to the season, with Froome winning the Tour of Oman and performing well in Tirreno-Adriatico and Richie Porte triumphing in the Paris-Nice race Wiggins won last year.

Critics have suggested Team Sky's scientific approach has taken the romance out of racing, while the British squad has been the subject of innuendo relating to doping.

Brailsford, Wiggins and others have issued firm rebuttals to the suggestions Team Sky's performances are unethical and Roche believes the insinuations are a by-product of success.

Roche, who is this week riding in a HotChillee team in the world's largest and toughest mountain bike race, the Absa Cape Epic in South Africa, said: "When you get a winning team, it's great. When they start dominating straight away, it can upset a lot of people.

"When you look at Sky, they've upset the apple cart over the last few years. Everybody looks at them and says they're destroying the sport, but we mustn't forget they've brought a lot of good to the sport.

"If Brailsford was to cheat somewhere along the line, he'll put on the line everything he has done.

"He's got an impeccable reputation. For that reason alone I think he'd be very reluctant to go down that road."